Ultracool Dwarfs

Ultracool Dwarfs PDF Author: Hugh R.A. Jones
Publisher: Springer Science & Business Media
ISBN: 3642566723
Category : Science
Languages : en
Pages : 199

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Book Description
Once you have looked at the night sky on a moonless night it is not hard to realise why so much of our science and religion has its roots in the stars. Yet it took until 1850 to realise that fainter stars were not necessarily further away, nor the brighter ones closer. In fact within the magnitude range observable to the naked eye it is probable that the brighter star is in fact further away. Even today the measurement of stellar distances is relatively difficult and is gener ally only done using dedicated telescopes. In the early years of the 20th century Hertzsprung and Russell developed a powerful classification diagram which al lows stars to be distinguished using a plot of their colour versus magnitude. The construction of this diagram involved the use of spectroscopy which has become the cornerstone of modern astronomy. As telescopes become more powerful, de tectors more sensitive and more physics is added to astrophysics, astronomical spectroscopy becomes a more powerful tool. The concern of this book is the spectral classification of stars. With a single spectrum of a star it is possible to uniquely classify an object and find its place on the Hertzsprung-Russell diagram. This spectrum is thus equivalent to having the colour and the magnitude of the object which can in turn be related to mass and other quantities.

Ultracool Dwarfs

Ultracool Dwarfs PDF Author: Hugh R.A. Jones
Publisher: Springer Science & Business Media
ISBN: 3642566723
Category : Science
Languages : en
Pages : 199

Get Book Here

Book Description
Once you have looked at the night sky on a moonless night it is not hard to realise why so much of our science and religion has its roots in the stars. Yet it took until 1850 to realise that fainter stars were not necessarily further away, nor the brighter ones closer. In fact within the magnitude range observable to the naked eye it is probable that the brighter star is in fact further away. Even today the measurement of stellar distances is relatively difficult and is gener ally only done using dedicated telescopes. In the early years of the 20th century Hertzsprung and Russell developed a powerful classification diagram which al lows stars to be distinguished using a plot of their colour versus magnitude. The construction of this diagram involved the use of spectroscopy which has become the cornerstone of modern astronomy. As telescopes become more powerful, de tectors more sensitive and more physics is added to astrophysics, astronomical spectroscopy becomes a more powerful tool. The concern of this book is the spectral classification of stars. With a single spectrum of a star it is possible to uniquely classify an object and find its place on the Hertzsprung-Russell diagram. This spectrum is thus equivalent to having the colour and the magnitude of the object which can in turn be related to mass and other quantities.

Low-mass Ultra-cool Dwarfs

Low-mass Ultra-cool Dwarfs PDF Author: Subhanjoy Mohanty
Publisher:
ISBN:
Category :
Languages : en
Pages : 582

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Book Description


Very Low-Mass Stars and Brown Dwarfs

Very Low-Mass Stars and Brown Dwarfs PDF Author: Rafael Rebolo
Publisher: Cambridge University Press
ISBN: 9780521663359
Category : Science
Languages : en
Pages : 284

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Book Description
This volume provides a state-of-the-art review of our current knowledge of brown dwarfs and very low-mass stars. The hunt for and study of these elusive objects is currently one of the most dynamic areas of research in astronomy for two reasons. Brown dwarfs bridge the gap between stars and planets, and they may constitute an important part of the 'dark matter' of the Universe. This volume presents review articles from a team of international authorities who gathered at a conference in La Palma to assess the spectacular progress that has been made in this field in the last few years.

New Light on Dark Stars

New Light on Dark Stars PDF Author: Neil Reid
Publisher: Springer Science & Business Media
ISBN: 3540276106
Category : Science
Languages : en
Pages : 590

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Book Description
There has been very considerable progress in research into low-mass stars, brown dwarfs and extrasolar planets during the past few years, particularly since the fist edtion of this book was published in 2000. In this new edtion the authors present a comprehensive review of both the astrophysical nature of individual red dwarf and brown dwarf stars and their collective statistical properties as an important Galactic stellar population. Chapters dealing with the observational properies of low-mass dwarfs, the stellar mass function and extrasolar planets have been completely revised. Other chapters have been significantly revised and updated as appropriate, including important new material on observational techniques, stellar acivity, the Galactic halo and field star surveys. The authors detail the many discoveries of new brown dwarfs and extrasolar planets made since publication of the first edition of the book and provide a state-of-the-art review of our current knowledge of very low-mass stars, brown dwarfs and extrasolar planets, including both the latest observational results and theoretical work.

Radiative Transfer in Stellar and Planetary Atmospheres

Radiative Transfer in Stellar and Planetary Atmospheres PDF Author: Lucio Crivellari
Publisher: Cambridge University Press
ISBN: 1108603092
Category : Science
Languages : en
Pages : 251

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Book Description
Radiative transfer is essential for obtaining information from the spectra of astrophysical objects. This volume provides an overview of the physical and mathematical background of radiative transfer, and its applications to stellar and planetary atmospheres. It covers the phenomenology and physics of early-type and late-type stars, as well as ultra-cool dwarf stars and extrasolar planets. Importantly, it provides a bridge between classical radiative transfer and stellar atmosphere modelling and novel approaches, from both theoretical and computational standpoints. With new fields of application and a dramatic improvement in both observational and computational facilities, it also discusses the future outlook for the field. Chapters are written by eminent researchers from across the astronomical disciplines where radiative transfer is employed. Using the most recent observations, this is a go-to resource for graduate students and researchers in astrophysics.

Astrophysics in the Next Decade

Astrophysics in the Next Decade PDF Author: Harley A. Thronson
Publisher: Springer Science & Business Media
ISBN: 1402094574
Category : Science
Languages : en
Pages : 523

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Book Description
NASA’s James Webb Space Telescope (JWST), planned for operation in about five years, will have the capability to investigate – and answer – some of the most challenging questions in astronomy. Although motivated and designed to study the very early Universe, the performance of the observatory’s instruments over a very wide wavelength range will allow the world’s scientific community unequaled ability to study cosmic phenomena as diverse as small bodies in the Solar System and the formation of galaxies. As part of preparation to use JWST, a conference was held in Tucson, Arizona in 2007 that brought together astronomers from around the world to discuss the mission, other major facilities that will operate in the coming decade, and major scientific goals for them. This book is a compilation of those presentations by some of the leading researchers from all branches of astronomy. This book also includes a “pre-history” of JWST, describing the lengthy process and some of the key individuals that initiated early work on the concepts that would evolve to become the premier space observatory of the next decade.

Extrasolar Planets

Extrasolar Planets PDF Author: Hans Deeg
Publisher: Cambridge University Press
ISBN: 1139468049
Category : Science
Languages : en
Pages : 269

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Book Description
This 2007 volume presents the lectures from the sixteenth Winter School of the Instituto de Astrofísica de Canarias, which was dedicated to extrasolar planets. Research into extrasolar planets is one of the most exciting fields of astrophysics, and the past decade has seen a research leap from speculations on the existence of planets orbiting other stars to the discovery of around 200 planets to date. The book covers a wide range of issues, from the state-of-the-art observational techniques used to detect extrasolar planets, to the characterizations of these planets, and the techniques used in the remote detection of life. It also looks at the insights we can gain from our own Solar System, and how we can apply them. The contributors, all of high-standing in the field, provide a balanced and varied introduction to extrasolar planets for research astronomers and graduate students, bridging theoretical developments and observational advances.

Multiple Stars across the H-R Diagram

Multiple Stars across the H-R Diagram PDF Author: Swetlana Hubrig
Publisher: Springer Science & Business Media
ISBN: 3540747451
Category : Science
Languages : en
Pages : 304

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Book Description
This volume presents results from the ESO workshop Multiple Stars across the H-R Diagram, held in Garching in July 2005. It covers observations of multiple stars from ground and space, dynamical and stellar evolution in multiple systems, formation and early evolution of multiple stars, and special components of multiple stars. The book reviews the current state of observational and theoretical knowledge and discusses future studies for further progress in the field.

Precision Spectroscopy in Astrophysics

Precision Spectroscopy in Astrophysics PDF Author: Nuno C. Santos
Publisher: Springer Science & Business Media
ISBN: 3540754849
Category : Science
Languages : en
Pages : 664

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Book Description
High-accuracy Doppler shift measurements and high-precision spectroscopy are primary techniques in the search for exo-planets. Further extremely interesting applications include the analysis of QSO absorption lines to determine the variability of physical constants and the analysis of the isotopic ratios of absorption lines both in stars and in QSOs, and the determination of stellar oscillations through radial velocity measurements. Since the use of high-precision/resolution spectroscopy is closely connected to the ability to collect a large number of photons, the scientific domains using this technique benefit tremendously from the use of 8-meter class telescopes and will fully exploit the tremendous gain provided by future Extremely Large Telescopes (ELTs). IR high-resolution spectroscopy should soon approach the same accuracy regime achieved in the optical range. This volume comprehensively covers the astrophysical and technical aspects of high-precision spectroscopy with an outlook to future developments, and represents a useful reference work for researchers in those fields.

The Initial Mass Function 50 Years Later

The Initial Mass Function 50 Years Later PDF Author: Edvige Corbelli
Publisher: Springer Science & Business Media
ISBN: 1402034075
Category : Science
Languages : en
Pages : 551

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Book Description
Theideatocelebrate50yearsoftheSalpeterIMFoccurredduringtherecent IAU General Assembly in Sydney, Australia. Indeed, it was from Australia that in July 1954 Ed Salpeter submitted his famous paper "The Luminosity Function and Stellar Evolution" with the rst derivation of the empirical stellar IMF. This contribution was to become one of the most famous astrophysics papers of the last 50 years. Here, Ed Salpeter introduced the terms "original mass function" and "original luminosity function", and estimated the pro- bility for the creation of stars of given mass at a particular time, now known as the "Salpeter Initial Mass Function", or IMF. The paper was written at the Australian National University in Canberra on leave of absence from Cornell University (USA) and was published in 1955 as 7 page note in the Astroph- ical Journal Vol. 121, page 161. To celabrate the 50th anniversary of the IMF, along with Ed Salpeter’s 80th birthday, we have organized a special meeting that brought together scientists involved in the empirical determination of this fundamental quantity in a va- ety of astrophysical contexts and other scientists fascinated by the deep imp- cations of the IMF on star formation theories, on the physical conditions of the gas before and after star formation, and on galactic evolution and cosmology. The meeting took place in one of the most beautiful spots of the Tuscan countryside, far from the noise and haste of everyday life.